Tube extension for spinning tube



July 25, 1961 c, Aws ETAL 2,993,229

TUBE EXTENSION FOR SPINNING TUBE FIG.1

1 INVENTORJ. CECIL F. Lnws WILLIAM R. NEwsoME,

r THEODORE E. PATT N. and N I'II'II'I'IIIIII'IJI'IA 5110 K5 H, wmr "U35171a! July 25, 1961 C. F. LAWS ETAL TUBE EXTENSION FOR SPINNING TUBE 2Sheets-Sheet 2 Filed March 13, 1957 A0 i q 1 FIG INVENTORS. CECIL F.LAWS, WILLIAM R. NEwsoMz, mconuns .PRTTOMami BROOKS M. wHlTEHUlsr BYMU/fab Patented July 25, 1961 2,993,229 TUBE EXTENSION FOR SPINNING TUBECecil F. Laws, Morristown, and William R. Newsome and Theodore E.Patton, Lowland, Tenn, and Brooks M. Whitehurst, Richmond, Va.,assignors to American Enka Corporation, Enka, N.C., a corporation ofDelaware Filed Mar. 1'3, 1957, Ser. No. 645,761 2 Claims. (Cl. 18--8)This invention relates in general to the production of artificial yarnand more particularly to an improved apparatus for the high speedextrusion of viscose yarn by the tube-spinning system.

It is known that a high tenacity viscose yarn can be produced ifregeneration of the viscose is retarded by means of a chemical retardantsuch as hexamethylenediamine, mon-isopropanol, etc., which retardantsmay be added either to the viscose spinning solution or to the spinbathinto which the viscose is extruded, or to both. Although viscose spun bythe use of one of these retardants ultimately produces a higher qualityyarn than heretofore known, this yarn is extremely tender in the earlystages of regeneration and must not be subjected to excess tension orabrupt treatment in the spinbath. Accordingly, first experiments in theuse of retardants necessitated a reduction in spinning speed in order toprevent adverse effect on the yarn by turbulence created in thespinbath. This, of course, was undesirable from an economical standpointsince a given spinning machine would produce less yarn than before in agiven period of time.

Subsequent to the aforesaid early experiments, it was found that thespinning speed could be increased substantially without deleteriouslyaffecting the tenacity and quality of the yarn produced by theretardants, if the yarn were spun into and passed through a confinedliquid treating zone, such as the two-diameter elongated spinningchamber or tube shown in copending application Serial No. 556,256, filedDecember 29, 1955, now Patent No. 2,908,937, dated October 29, 1959,which is owned in common herewith. In that application yarn is extrudedfrom a spinneret into the small diameter portion of the tube, afterwhich it passes into the large diameter portion, around suitable guiderollers and to a draw godet. The spinneret, two-diameter tube and firstguide roller are submerged in a relatively large spinbath containingsulphuric acid and a small percentage of a chemical retardant.

During normal operation of the above described apparatus, yarn drawnthrough the two-diameter tube from the spinneret by the draw godetexerts a frictional pumping force in the direction of yarn travel on theliquid contained within the large portion of the tube, which creates asucking action on the liquid in the small portion, resulting in acontinuous flow of liquid from the spinbath through the tube in responseto travel of the yarn therethrough. The flow speed of the liquid isdependent upon the speed of the yarn and the size of the tube throughwhich the yarn and liquid travel. This process subjects the yarn to verylittle tensional force in the early and critical stages of regenerationand produces high tenacity yarn at high spinning speed since, whenoperating under proper conditons, the liquid flow assists rather thanimpedes travel of the yarn through the tube. It has now been found,however, that the foregong process can be improved still further bypractice of the invention which is to be described in detailhereinbelow.

Accordingly, an object of the present invention is to provide animproved apparatus for producing viscose yarn by the tube-spinningprocess.

further object of the present invention is to provide an improvedapparatus for producing high tenacity viscose yarn.

Still another object of this invention is to provide an improvedapparatus for producing high quality viscose yarn at high spinningspeeds.

Another object of this invention is to provide a novel apapratus fordeflecting a running length of freshly extruded yarn from a spinbathsolution or regenerating liquid flowing in the same direction as that ofthe yarn with a minimum of turbulence.

An additional object of this invention is to provide a novel means forpositioning the tube of a tube-spinning machine with respect to thespinneret of that machine.

A further object of this invention is to provide a novel apparatusadaptable for use in the tube-spinning of viscose yarn for uniformlydispersing liquid discharging from the tube and for preventing theformation of foam.

The objects of the present invention may be accomplished by extruding aviscose solution through a spinneret which is submerged in a spinningtank containing sulphuric acid, drawing the freshly spun yarn and astream of the acid bath in co-current direction through a confinedtreating zone or tube, removing a portion of the bath from the flowingstream at a point outside the spinning tank and thereafter separatingthe partially regenerated yarn from the flowing stream of remaining acidbath. One end of the tube is positioned adjacent to and in alignmentwith the face of the spinneret whereas the other end of this tubeextends outside the spinning tank into a separate compartment,hereinafter referred to as a chimney. Within the chimney and inalignment with the tube there may be mounted a tube extension, whichextension supports a thread guide means, such as a freely rotatableguide or deflector roller. The extension and roller senve as a means forseparating the freshly extruded yarn from the acid bath while subjectingthe yarn to the least possible turbulence and only slight tensionalforce due to frictional drag of the acid on the yarn.

These and further objects and advantages of this invention will becomeapparent upon study of the following detailed description taken inconjunction with the annexed drawings, wherein:

FIGURE 1 is an elevational view, partially in section along the lines1-1 of FIGURE 2, illustrating one spinning unit of a spinning machinemodified in accordance with the teachings of the present invention andshowing conventional structure only when such is considered essential toa complete understanding of this disclosure;

FIGURE 2 is a plan view of the apparatus shown in FIGURE 1, taken alongthe lines 2-2 of that figure; and

FIGURE 3 is an isometric view of the tube extension per se.

Referring now to the drawings, which show a preferred embodiment of thisinvention, and particularly to FIG- URE 1, reference numeral 10designates the upper portion of a spinning tank which contains the mainsupply of spinbath 11. This tank may be supported from the floor of thespinning room by any suitable means (not shown), and the longitudinalaxis thereof extends generally horizontally, as shown. Within spinningtank 10 there is positioned a spinneret 12, an inclined two-diametertube 13 and a chimney 14. The spinneret 12 and small diameter portion 15of tube 13 are removably held in spaced but aligned position bysupporting bracket 16 which is secured to the bottom plate of the tank,as can be seen from the drawing. The large diameter portion 17 of tube13 extends into and is removably supported within one wall of chimney 14by a sealing ring 18 constructed from rubber or any other elasticmaterial which is not affected by the acid contained in spinbath 11.

A viscose solution is pumped to spinneret 12 from a a candle filter (notshown) through viscose supply line 21). The filaments extruded from thespinneret are threaded into and through the two-diameter tube 13 in amanner to be explained more fully hereinafter.

As shown in FIGURE 2, the chimney 14, into which the large diameterportion of tube 13 discharges both freshly spun yarn and a portion ofspinbath 11, consists essentially of a vertical compartment defined onthree sides by front wall 21, side wall 22 and rear wall 23,respectively, which structure resembles generally a channel beam, and onthe fourth side by wall 24 of spinning tank 10. Chimney 14 is supoprtedby flanges 25 which extend laterally from the bottom thereof and whichrest on the upper surface of spinning tank bottom plate 26. In order toprevent flow of spinbath 11 into chimney 14 except through tube 13, theexposed longitudinal edges of both walls 21 and 23 are sealed to thespinning tank wall 24, and the flanges 25 are sealed to the bottom plate26, as illustrated in FIGURES 1 and 2.

An opening 27 is cut or otherwise formed in the bottom plate 26 of tank10. This opening, which is vertically aligned with the compartmentdefined -by Walls 21, 22, 23 and 24, permits flow of the spent orweakened spinbath downwardly in the direction of the arrow into a gutter(not shown) which directs flow of the bath to a recirculation zone (alsonot shown). In this zone, fresh make-up acid is added to and mixed withthe weakened spinbath and the composite solution is fed under pressureto a supply acid trough and then to the spinning tank 111 through ports28, as indicated by arrows in FIGURE 1. In this manner that portion ofthe spinbath which is pumped through tube 13 and weakened by exposure tothe freshly extruded filaments is reclaimed and eventually recirculated.

Fixed within chimney 14 and in parallel or spaced alignment with thelongitudinal axis of tube 13 is a tube extension indicated generally byreference numeral 30. This extension consists in ledges 31 and 32 whichextend substantially parallel one to the other and which define a trough33 therebetween, as can be seen in FIGURE 3. The trough 33 is ofsemi-circular cross-section and of a diameter slightly larger than theouter diameter of tube portion 17. This trough, in cooperation with theopening in chimney wall 23 and the ring 18, forms a cradle into whichthe discharge end of tube 13 is snugly but removably positioned.

In order to accurately position the tube 13 with respect to the tubeextension and also with respect to the spinneret 12, a projection 34 isformed in the bottom surface of trough 33. This projection serves as astop and limits movementof the tube in a forward direction, or in thedirection of yarn travel, as can be seen in FIGURE 1 of the drawings.Inasmuch as the yarn and a stream of the spinbath solution flow throughthe tube 13 in a direction toward the tube extension, the tendency ofthis movement is continuously to urge the tube into engagement with theprojection 34.

One end of a stub shaft 35 is fixed to the upper surface of ledge 31adjacent to the discharge end thereof and projects inwardly and upwardlyat an angle therefrom into general vertical alignment with the trough33. Shaft 35 as shown forms a bearing surface on which guide roller 36is rotatably mounted although it is obvious that this shaft could beutilized as a guide bar capable of defleeting the yarn. The guide rolleris circumferentially grooved in a manner known to the art and deflectsthe yarn issuing from the tube and trough to a substantially verticaldirection of travel, as shown in FIGURE 1, which of course separates theyarn from the moving body of regenerating solution. The groove apex onthe lower side of roller 36 is in alignment with the longitudinal axisof tube 13 and serves to position the yarn centrally of the tube andtrough. The yarn path and longitudinal axis of tube 13 extend slightlyabove the upper surface of ledge 31 at the discharge end of the tube.This allows excess tit! liquid discharging from the tube to spill out oftrough 33, which reduces the turbulence around the filaments between theoutlet end of the 'tube and the deflector roller 36 and consequentlyprevents breakage and wrapping of individual filaments around thisroller. It is to be noted, however, that a sufiicient amount of liquidflows to the end of the trough 33 to maintain the yarn submerged in thesurface layer thereof until it is deflected by roller 36.

Tube extension 30 further comprises and has formed unitarily therewith awedge-shaped baflie plate 37 which extends laterally from ledge 31 andlongitudinally from the discharge end of trough 33. When the tubeextension is mounted within chimney 14, the baflle plate serves tosupport trough 33 in the chimney and also to seal a portion of the upperextremity thereof. The baffle plate does not extend to wall 21, however,but is designed to define an opening 38 through which the weakenedspinbath discharging from trough 33 may flow.

In order to expedite mounting of the necessary number of spinning unitsin a conventional spinning machine, tube 13 and chimney 14 are angularlydisposed with respect to the vertical plane of spinning tank wall 24, ascan be seen in FIGURE 2. Moreover, the tube 13 and tube extension 36 aredisposed at an angle of approximately 4 degrees with respect to ahorizontal plane, as can be seen in FIGURE 1. This angular dispositionensures submersion of the spinneret 12 and entrance end of tube 13 anamount necessary to prevent a vortex of the spinbath which would pullair into the tube and therefore create undesirable turbulence. Thedischarge end of tube 13 is positioned sufliciently below the surface ofspinbath 11 to ensure a uniform flow with a minimum of turbulence. Theinclination of the tube also expedites discharge of carbon disulfideliberated from the spinbath upon contact of the same with the freshlyextruded yarn, which also tends to reduce turbulence in the spinbath.Godet 40, which is driven in a known manner, draws yarn from thespinneret 12, through tube 13 and around guide roller 36, this actionalso serving to pump spinbath through the tube as explained earlier.

Baffle plate 37 extends downwardly at an angle of approximately 15degrees with respect to the longitudinal axis of trough 33 and servesnot only to uniformly disperse the liquid emerging from the trough butalso to prevent the formation and rise of foam in the chimney.

The spinning tank, chimney, tube extension and tube supporting bracketmay be constructed from lead or any other acid-resistant material andthe tube 13 may be constructed from Pyrex glass. The flanges of chimney14 and tube extension may be burned into position in a manner known tothe art. The stub shaft may also be burned into position within trough33.

Example Alkali cellulose prepared in a known manner was reacted with34.4% carbon disulfide. The resulting xanthate was dissolved in a sodiumhydroxide solution to produce viscouse having the composition of 7.75%cellulose and 5.53% sodium hydroxide. This solution was modified byadding a chemical retardant. The spinning viscosity of 20 C. was 57seconds (ball-fall) and the viscose had a xanthate ratio of .46.

The viscose solution prepared in the manner described above Was spuninto 1650/ 720 filament yarn by extruding through a spinneret into acoagulating and regenerating bath containing 6.15% sulfuric acid, 18.4%sodium sulfate, 3.5% zinc sulfate and 35 ppm. lauryl pyridiniumchloride. The temperature of the bath was maintained at 68 C.

The filaments extruded through the spinneret were fed into atwo-diameter tube having a first portion with an inside diameter of 21mm. extending for a length of 509 mm. and a second portion with aninside diameter of 27 mm. extending for a length of 240 mm., with atransition section of 60 mm. length connecting these two portions. Theacid level before spinning in was maintained at approximately 60 mm.above the center of the tube at the entrance end and approximately 14.75mm. above the center of the tube at the discharge end. During spinning,this level was lowered slightly due to the pumping action of the yarntraveling through the tube. The yarn was drawn by a first godet throughthe tube at a rate of 39.4 meters/minute and led to a hot water bath. Bythe combined pumping action of the yarn, as stated above, and the slightliquid head in the spinbath, acid was forced through the small diameterportion of the tube at a rate of 35.5 meters/minute and through thelarge diameter portion at a rate of 21.5 meters/minute. From the hotwater bath the yarn was passed around a second godet traveling at aperipheral speed of approximately 75 meters/minute so as to impart astretch of approximately 90% to the yarn. The stretched yarn wascollected in cake form in a bucket and after-treated in known manner.The tenacity of the yarn produced was 432 grams/ 100 denier and thepercent elongation of slashed singles was 10.8.

The face of the spinneret was positioned approximately 21 mm. from thetrumpet shaped entrance end of the spinning tube. Upon spinning in,filaments emerging from the spinneret were led into the entrance end ofand through the tube by the acid which was caused to flow therethroughby virtue of the liquid head discussed above.

As pointed out hereinbefore, the discharge end of tube 13 projectsthrough a suitable opening provided in wall 23 of chimney 14 and restsagainst projection 34 of tube extension 30. The yarn and acid bath passfrom the tube into trough 33, as can be seen from the drawings. In orderto dispose of excess acid and prevent turbulence, the ledge 31 of tubeextension 30 extends parallel with but approximately below the path ofyarn travel, thus permitting a small portion of the acid to spill overthe ledge and drain down plate 37 through opening 38 into the verticalcompartment defined by chimney 14. The remainder of acid travels withthe yarn down trough 33 to guide roller 36, at which point the yarn isdeflected upwardly from the path of flowing acid with a minimum ofturbulence. This portion of acid thereafter also drains down baflieplate 37 into the compartment below, after which it may be reclaimed andrecirculated in a manner described supra.

It has been found that a A differential between the height of ledge 31and the yarn path, as explained herein, maintains the level of acidflowing through trough 33 at a height substantially equal to the apex ofthe groove on the lower side of roller 36 and thus prevents the buildingup of this acid level between the roller and discharge end of tube 13,which would result in a turbulent flow of acid producing filament breaksand entanglements with the roller. The yarn remains immersed in a bodyof smoothly flowing acid, however, until the same is deflected by guide6 roller 36. It will be evident from the foregoing that the acid flowsin a direction co-current with the yarn until the yarn is suddenlydeflected or separated therefrom by the guide roller.

By the use of the above-described device it was found that high tenacityviscose yarn could be produced at high spinning speeds. This was due tothe manner in which the freshly extruded yarn and spinb-ath were drawnthrough the confined treating Zone and to the manner in which the yarnwas separated from the spinbath with a minimum of turbulence. Moreover,that portion of the spinbath flowing into the vertical compartmentdefined by the chimney was dispersed uniformly over the baffle plate,which prevented the formation and subsequent rise of foam in thiscompartment and contributed to a more uniform circulation of thespinbath solution. Additionally, it was found that by the use of thetube extension described herein, the treating tube could be more easilyand quickly positioned with respect to the spinneret, re sulting in aconsiderable saving of time with respect to a complete spinning machineof the tube type.

It is understood that the foregoing description is for purposes ofillustration only and is not intended to limit the scope of thisinvention except to the extent defined in the following claims.

What is claimed is:

1. A tube extension comprising an elongated supporting plate, a pair ofledges extending longitudinally of said plate and forming thereon atrough, a baffle extending outwardly of said supporting plate in generalalignment therewith but inclined with respect to the trough formed bysaid pair of ledges, and a guide roller secured to one of said ledgesand extending into general vertical alignment with said trough, thelower peripheral surface of said guide roller being disposed slightlyabove the upper edges of said ledges.

2. A tube extension as set forth in claim 1 and further comprising meansprojecting into said trough adjacent an end thereof opposite said baffleand forming a stop for positioning a tube with respect thereto.

References Cited in the file of this patent UNITED STATES PATENTS2,040,607 Hartmann May 12, 1936 2,273,240 Wesp Feb. 17, 1942 2,467,541Taylor Apr. 19', 1949 2,550,808 Hays May 1, 1951 2,690,663 McDermottOct. 5, 1954 2,739,712 Pedlow Mar. 27, 1956 2,789,315 Pistor Apr. 23,1957 2,793,396 Dooley May 28, 1957 2,800,682 Dooley July 30, 19572,849,751 Sonnino Sept. 2, 1958

